An air battery is a battery employing oxygen as a cathode active material; at the time of discharge, air is introduced from outside the battery. So, compared with other type of batteries which incorporate active materials for both cathode and anode, it is possible to enlarge the occupancy rate of the anode active material in the battery case. Hence, in principle, such an air battery has features that dischargeable electric power is large, besides, as downsizing and weight saving can be easily realized. In addition, oxidation power of oxygen to be employed as the cathode active material is strong so that the electromotive force is relatively high. Moreover, since oxygen is a clean resource the amount of which is not limited, the air battery is environmentally-friendly. As above, air battery has many advantages; therefore it is expected to be used for batteries for mobile devices, electric vehicles, hybrid cars, and fuel-cell-powered vehicle.
With regard to an air battery using a metal as the anode, when water enters into a battery, the water and the anode tend to react. If the water and the anode react, it predicts that the air battery may be deteriorated. So, to inhibit deterioration of the air battery, presumably, it is important to avoid contact between the anode and water.
As an art related to such an air battery, for example, Patent literature 1 discloses an art to inhibit contact of an anode and water by giving hydrophobic nature to the non-aqueous electrolyte using a room-temperature molten salt as a non-aqueous electrolyte of the air battery, such as trimethyl propylammonium bis(trifluoromethylsulfonyl)imide.